This invention relates to a fuel system for an internal combustion engine, and more particularly to a fuel system including a pressure regulator for a vehicle powered by a fuel injected internal combustion engine.
Most modern automotive fuel systems utilize fuel injectors to deliver fuel to the engine cylinders for combustion. The fuel injectors are mounted on a fuel rail to which fuel is supplied by a pump. The pressure at which the fuel is supplied to the fuel rail must be metered to ensure the proper operation of the fuel injectors. Metering is carried out using pressure regulators that control the pressure of the fuel in the system at all engine r.p.m. levels.
Fuel flow rate, measured in liters per hour, through known pressure regulators tends to be low at high engine speed, measured in revolutions per minute, as large quantities of fuel are consumed in the combustion process. At low engine speeds, less fuel is consumed in combustion and flow rates through the pressure regulators are high. These high fuel flow rates can produce unacceptably high noise and pressure levels.
According to a known fuel system, as shown in FIG. 8, gasoline is stored in a tank on-board a vehicle. The gasoline is withdrawn from the tank by a pump and fed through a filter to fuel injectors, which deliver the gasoline to combustion cylinders in the engine. The fuel injectors are mounted on a fuel rail to which fuel is supplied by the pump. The pressure at which the fuel is supplied to the fuel rail must be metered to ensure the proper operation of the fuel injectors. Metering is carried out using pressure regulators that control the pressure of the fuel in the system at all levels of engine speed.
A first known pressure regulator, as shown in FIG. 9, includes a spring biased valve seat with a longitudinal flow passage. The longitudinal flow passage, which has a constant cross-section orthogonal to a longitudinal axis, can be modified for length along the longitudinal axis to slightly modify noise and flow performance characteristics.
A second known pressure regulator, as shown in FIG. 10, includes a necked-down longitudinal flow passage and mutually orthogonal cross-drilled holes. The cross-drilled holes disperse fluid flow in a manner that is effective to improve the noise and flow characteristics of the known regulator shown in FIG. 9. However, manufacturing a seat with the necked-down longitudinal flow passage and cross-drilled holes is costly to machine.
It is believed that there is a need for a fuel system that uses a pressure regulator that is less expensive to manufacture and maintains flow-related noise and pressure within acceptable levels, even at high fuel flow rates.
The present invention provides a fuel system for an internal combustion engine powered by fuel. The fuel system includes a fuel tank adapted to contain the fuel, a pump adapted to withdraw the fuel from the tank and to pressurize the fuel, a pressure regulator, and piping connecting the fuel tank and pump, the piping adapted to supply fuel to the internal combustion engine. The pressure regulator includes a perforated diaphragm-to-seat retainer and provides at least one of generally constant flow-related noise at all fuel flow rates and generally uniform pressure at all fuel flow rates.
The present invention also provides a method of supplying fuel by a pump from a tank to an internal combustion engine. The method includes pumping the fuel under pressure, and regulating fuel flow from the pump. The regulating includes passing the fuel through a diaphragm-to-seat retainer that has been perforated with a plurality of apertures.